Syntheses of epoxysilicones

ABSTRACT

The invention provides a process for producing epoxy-functional silicones by a rhodium metal complex-catalyzed hydrosilation reaction between an SiH-containing silane or siloxane and an olefin epoxide, in the presence of a tertiary amine stabilizer. In practicing the invention, RhCl 3  [(CH 3  (CH 2 ) 3 ) 2  S] 3  or PtCl 2  [(CH 3  CH 2 ) 2  S] 2  are suitable hydrosilation catalysts and methyldicocoamine, CH 3  (C 18  H 37 ) 2  N, is a suitable stabilizer. The invention also provides for a composition including an SiH-functional silane or siloxane, and a tertiary amine, where the composition is not susceptible to gelation during a hydrosilation addition reaction. The invention further provides a method for stabilizing epoxysilicones both during and after the hydrosilation addition reaction used in their production.

This application is related to commonly assigned U.S. patentapplications entitled, "UV-CURABLE EPOXYSILICONE-POLYETHER BLOCKCOPOLYMERS, Ser. No. 07/802,679 filed Dec. 5, 1991, and "IMPROVEDSYNTHESES OF EPOXYSILICONES", Ser. No. 07/802,681 filed Dec. 5, 1991, adivision of the aforementioned Ser. No. 07/802,679, which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

The invention relates to a process for producing epoxy-functionalsilicones by a hydrosilation reaction between an SiH-functional silaneor siloxane and an olefin epoxide, wherein gelation during processing,due to thermally-induced epoxide-mediated crosslinking is eliminated byuse of certain rhodium or platinum sulfonium hydrosilation catalysts incombination with a tertiary amine stabilizer. The invention also relatesto an epoxysilicone composition that is stable to epoxide-mediatedcrosslinking both during and after a hydrosilation reaction, as well asto a method for stabilizing olefin epoxides and epoxysilicones in thepresence of a hydrosilation catalyst and SiH-functional group.

The hydrosilation reaction of unsaturated epoxides to SiH-functionalizedsilicone polymers has long been recognized as an elegant and convenientroute to the manufacture of functionalized silicone materials.Epoxysilicone polymers are conveniently manufactured through thehydrosilation reaction between a SiH-functionalized silicone and olefinepoxide. The general hydrosilation reaction for silanes can be expressedas

    .tbd.SiH+CH.sub.2 ═CH--Q→.tbd.Si--CH.sub.2 --CH.sub.2 --Q

and the general hydrosilation reaction for siloxanes can be expressed as

    --((H) (Q')SiO)--+CH.sub.2 ═CH--Q→--((Q--CH.sub.2 --CH.sub.2)(Q')SiO)--

where Q and Q' represent an organic radical. These reactions, as well ashydrosilation reactions in general, are known to be catalyzed byplatinum compounds. However, as disclosed in commonly assigned U.S.patent application Ser. No. 07/473,802, filed Feb. 2nd, 1990, it hasbecome apparent that the same platinum reagents used in the catalysis ofthe hydrosilation reaction to generate heterocyclic epoxy-functionalizedsilicones also promotes a highly undesirable epoxy ring-openingreaction. This latter reaction results in crosslinking and prematuregelling of an epoxysilicone in the presence of SiH groups and theplatinum hydrosilation catalyst species. The oxirane ring-opening sidereaction is particularly troublesome at the elevated temperaturesencountered during normal processing, but also serves to reduce theshelf life of epoxy-functionalized silicone products.

In order to partially circumvent the gelling caused by epoxidering-opening during the hydrosilation reaction, epoxysilicone fluidshave heretofore been produced using careful control of batch temperatureand olefin-epoxide feed rate during the addition reaction, and by use oflow levels of mercaptans to deactivate the platinum catalyst after thecompletion of the hydrosilation reaction. There remains, however, thepossibility that ring-opening polymerization will occur during any givenbatch synthesis.

Rhodium compounds are also known to catalyze the hydrosilation reactionbetween an SiH-functional silane or siloxane and an ethylenicallyunsaturated organic radicals. For example, see generally J. F. Harrodand A. J. Chalk, in "Organic Syntheses via Metal Carbonyls", Vol. 2, I.Wender and P. Pino, eds., pp. 685-687, John Wiley & Sons, New York; andJ. L. Speier, Advances in Organometallic Chemistry, Vol. 17, 407 (1979).Additionally, commonly assigned U.S. patent application entitled"Preparation of Epoxysilicon Compounds using Rhodium Catalysts",(Crivello and Fan) Ser. No. 07/583,524, filed Sep. 17, 1990, disclosesseveral rhodium catalysts suitable for use in the particularhydrosilation reaction between SiH-functional silanes or siloxanes andolefin epoxides. Also, U.S. Pat. No. 4,946,818 discloses that a rhodiumcolloid made by the reaction between rhodium chloride and certainsilicon hydrides is an effective hydrosilation catalyst, and U.S. Pat.No. 3,928,629 discloses a process in which a rhodium sulfide or rhodiumcarbonyl complex is used as catalyst for organohydrogenpolysiloxane-based release coatings.

Hydrosilation reactions between olefin epoxides andorganohydrogensiloxanes catalyzed with platinum metal complexescontaining rhodium have also been described. Reference is made to U.S.Pat. No. 4,279,717 (Eckberg) and to commonly assigned U.S. patentapplication Ser. Nos. 07/332,646, filed Apr. 3, 1989, and 07/473,802,filed Feb. 2, 1990.

A tertiary amine stabilizer for use with epoxy-functional silanes andsiloxanes has also been previously described in the above-mentioned,commonly assigned U.S. patent application of Crivello and Fan. In thatcase, a tertiary amine is added following the completion of the additionof olefin epoxide to ah SiH-functionalized silicone, but prior to thestripping of volatiles from the reaction product. Thus, the tertiaryamine stabilizer is not present during the addition reaction itself,such that epoxy crosslinking promoted by the elevated temperature of theaddition reaction often cannot be avoided.

Due to the undesirable ring opening reaction during the hydrosilationaddition, the reproducibility of the products obtained, particularlywith respect to viscosity, has heretofore been less than optimal. Therethus exists a need in the epoxysilicone industry for a hydrosilationreaction for the addition of epoxy-functionalized unsaturated compoundsto SiH-functionalized silanes and siloxanes, in which the epoxy-ringopening is greatly suppressed or eliminated. Preferably, the epoxyring-opening reaction would be eliminated throughout the course of theaddition reaction rather than only afterwards. In such a preferredscenario, the batch-to-batch reproducibility of the end-product, as wellas its shelf-life, would be substantially increased. All patents andreferences described herein are incorporated by reference.

SUMMARY OF THE INVENTION

The invention provides for improved hydrosilation syntheses ofepoxysilicones wherein certain rhodium and platinum sulfide compoundsare employed as catalyst in the presence of a tertiary amine stabilizer,the latter of which is included in a reaction mixture prior to theinitiation of the addition reaction. The process of the inventioneffectively prevents the premature gelling of epoxysilicone materialsduring both the addition reaction and subsequent processing and storage.Suitable hydrosilation catalysts for practicing the process of theinvention include compounds of the formulas RhX₃ (R¹ ₂ S)₃ and PtX₂ (R¹₂ S)₂, where X is a halogen other that F⁻, and R¹ is an alkyl, aryl,alkaryl or aralkyl, substituted or unsubstituted organic radical,preferably C.sub.(1-30) alkyl, and most preferably n-butyl or ethylradical. Suitable tertiary amine stabilizers in the process of theinvention are those of the formula R¹ ₃ N, wherein R¹ has theabove-stated meaning, and where each R¹ group may be the same ordifferent than the others. A preferred tertiary amine stabilizer in theprocess of the invention is methyldicocoamine, CH₃ (C.sub. 18 H₃₇)₂ N.The invention also provides for a composition comprising olefinepoxides, epoxysilicones and SiH-functional silanes or siloxanes, thatincorporates a tertiary amine to prevent the catalysis of oxirane ringopening reactions in the presence of SiH groups and hydrosilationcatalyst. The discovery of the present invention makes possible theproduction of highly reactive epoxysilicone fluids such as M.sup.εM.sup.ε and (D.sup.ε)₄, which were heretofore difficult to make withpreviously existing technology due to the strong tendency of thesecompounds to undergo acid-type, thermally induced and epoxy-mediatedcrosslinking during the addition reaction.

DETAILED DESCRIPTION OF THE INVENTION

Platinum catalysts in the presence of SiH-functionalized molecules andepoxy-functional silicones, generally promote a thermally inducedoxirane ring opening reaction of the epoxide, which thereby prematurelyinitiates a crosslinking reaction during the hydrosilation additionreaction. One object of the present invention is to provide a systemwherein the premature crosslinking of epoxysilicones due to the openingof oxirane rings is greatly suppressed or even eliminated throughout thecourse of both the addition reaction and subsequent processing steps.Although tertiary amines are known to stabilize the products of thereaction when added after the addition was completed, it was anunexpected finding that a tertiary amine stabilizer was useful to thissame end during the addition reaction itself, provided that certainrhodium or platinum catalysts are used to catalyze the additionreaction. This finding was surprising particularly since tertiaryamines, being basic in nature, generally would be expected to poisonprecious-metal catalysts typical of those used in for the hydrosilationreaction. Previously, this poisoning of the catalyst was one of the veryreasons that tertiary amine stabilizers were added after the additionreaction was completed. It was equally unexpected that onlysulfur-containing rhodium and platinum catalysts are active in thepresence of tertiary amines, while other well known hydrosilationcatalysts, for example phosphorus-containing rhodium catalysts, arepoisoned by the presence of the stabilizer. Thus, as exemplified below,the proposition that tertiary amines poison hydrosilation catalystslikely remains generally true.

The process of the invention is most generally the reaction between anSiH-functional silane or siloxane and an olefin epoxide in the presenceof a tertiary amine stabilizer. As would be readily recognized in theart, there are many silanes, polysiloxanes and their derivatives thatare suitable for use in the process and product of the presentinvention; the only general limitation being that there be at least onefunctional SiH group present on the molecule, such that the silicone iscapable of undergoing the hydrosilation addition reaction. For example,simple polysiloxanes of the general formula

    R.sup.2.sub.3 SiO(R.sup.3.sub.2 SiO).sub.n SiOR.sup.2.sub.3

where R² and R³ are, individually, hydrogen, or a substituted orunsubstituted alkyl group having from about 1 to 12, and preferablyabout 1 to 5 carbons; with the provision that at least two R² or R³groups are hydrogen; and n is from about 4 to about 1000, preferablyfrom about 1 to about 400 are suitable for use in the product andprocess of the invention. Throughout this disclosure and in the claimsappended hereto, by use of the term "substituted" it is meant an organicradical having chloro, bromo, iodo, cyano, carboxy, mercapto, hydroxy,thio, amino, nitro or other groups contained therein, as known in theart. Additionally, heterocyclic and aromatic heterocyclic organicradicals such as pyridyl, thiophenyl, pyranyl, and other as known in theart are also meant to be encompassed in the definition of "substituted"organic radicals. The process of the invention is additionally useful inthe preparation of silicone-organic copolymers, terpolymers, etc. as areknown in the art, provided that these polymers not be so acidic as toeffectively neutralize the action of the stabilizer.

Suitable olefin epoxides for use in the process and product of thereaction are limoneneoxide, 4-vinylcyclohexene oxide (VCHO),allylglycidylether, glycidylacrylate, 7-epoxy-1-octene, vinylnorborenemonoxide, dicyclopentyldiene monoxide and the like. Preferably theunsaturation in the olefin epoxides is terminally located on an alkylchain, as such bonds have been found to be more reactive in thehydrosilation reaction than those located internally. Most preferably,4-vinylcyclohexeneoxide is employed as the olefin epoxide in thepractice of the present invention.

Suitable catalysts for use in the process and product of the reactionare rhodium or platinum sulfide compounds of the general formula

    RhX.sub.3 (R.sup.1.sub.2 S).sub.3

and

    PtX.sub.2 (R.sup.1.sub.2 S).sub.2

where X is a halogen other than F⁻ and R¹ is C.sub.(1-30) alkyl, aryl,alkaryl or aralkyl, preferably C.sub.(1-20) alkyl and most preferablyC.sub.(1-10) alkyl and may be substituted or unsubstituted. Preferred inthe product and process of the invention is the use of RhCl₃ [(CH₃(CH₂)₃)₂ S]₃ or PtCl₂ [(CH₃ CH₂)₂ S]₂ or a mixture thereof.

Other common hydrosilation catalysts which are not operative in thepresent invention include Wilkinson's catalyst (RhCl((C₆ H₅)₃ P)₃),Lamoreaux's catalyst (H₂ PtCl₆ in octyl alcohol as described in U.S.Pat. No. 3,220,972), Spaier's catalyst (chloroplatinic acid) andKarlstedt's catalyst (platinum-silicone complex containing less than 0.1gram atom of halogen per gram atom of platinum). These catalysts areapparently poisoned by a tertiary amine.

Sulfur containing rhodium catalysts operative in the invention and themethod of their preparation are disclosed in U.S. Pat. No. 3,828,629(Chandra, et al.). As discussed in this reference, complexes of theformula RhX₃ (R² S)₃ in which the R groups are organic radicals that donot contain silicon can be prepared, for example, according to thedisclosure in Jour. Chem. Soc. (A), (1971), 899. Complexes having thissame general formula which contain silicon may be prepared by reactingtogether a rhodium halide RhX₃ and a silicon-containing sulphide R² S,preferably in the presence of a polar solvent.

The amount of catalyst added in the process of the invention isgenerally that which will affect a complete hydrosilation reactionbetween a organohydrogen siloxane and olefin epoxide in a suitable time,for example, in less than 2 hours. In general, the catalyst is best usedin an amount of from about 0.1 to about 50 parts per million, preferablyfrom about 1 to about 20 parts per million, and most preferably fromabout 2 to about 5 parts per million, each by weight of precious metalas compared to the weight of the curable composition.

In the process and product of the instant invention, a stabilizer isused to prevent the temperature-induced oxirane ring opening reaction.In general, stabilizers useful in the practice of the invention arebasic compounds. Three criteria in the choice of suitable stabilizersare that the compound prevent acid-type epoxide ring opening, not poisonthe hydrosilation catalyst, and that the stabilizer not be volatile orthermally unstable. This latter property is desirable since it isgenerally useful for the stabilizer to remain active after step ofstripping volatiles from the reaction mixture. It has been found thattertiary amines are particularly useful stabilizers for practice of theinvention. Suitable tertiary amines include substituted or unsubstitutedtrialkylamines, triarylamines, alkarylamines, aralkylamines and mixedamines comprising more than one of these substituents, for examplediethylphenylamine, diphenylethylamine, etc. A preferred tertiary amineis methyldicocoamine, CH₃ (C₁₈ H₃₇)₂ N.

In the product and process of the invention, the tertiary aminestabilizer is added to an Si--H functional silane or siloxane fluidbefore the addition of catalyst and subsequent addition of olefinepoxide. In this case, acid-type, thermally induced oxirane ring openingis prevented throughout the hydrosilation addition reaction. Also, asthe preferred tertiary amine of the present invention is not volatile,its stabilizing action remains effective throughout subsequentprocessing steps, particularly the step of stripping volatiles from thereaction product. Moreover, the preferred tertiary amine of the presentinvention is thermally stable and compatible with storage of theSi-functional silicones, so that batches of SiH-containing silane andsiloxane fluids can be premixed with the stabilizer in large scale forsubsequent use in the future as dictated by need.

For use in the present invention, tertiary amine stabilizer is added toa mix of SiH-functionalized siloxane and olefin epoxide at aconcentration sufficient to inhibit gelation, as is readily determinableby those of skill in the art. In general, the lowest level of tertiaryamine which is effective in preventing gelation is the choice amount.Tertiary amine stabilizer present at a concentration of from about 10 toabout 1000 ppm with respect to the weight of the curable resin, issufficient to practice the invention. Preferably, tertiary amines areused at a concentration of about 20 to about 500 ppm and most preferablyfrom about 50 to about 200 ppm, both as compared to the weight of thecurable composition.

In practicing the process of the present invention, an SiH-functionalsilane, siloxane or suitable SiH-functionalized derivative isconveniently mixed with the tertiary amine stabilizer, after which isadded a suitable rhodium or platinum sulfide hydrosilation catalyst,such as the preferred tris(di-n-butylsulfide) rhodium trichloride ofbis(diethylsulfide) platinum dichloride. The silane or siloxane is addedfrom about 20 to about 95 parts, by weight, whereas the olefin epoxideis added in from about 80 to about 5 parts by weight. The hydrosilationreaction is then conveniently initiated by the addition of olefinepoxide at mildly elevated temperatures. Preferably, the olefin epoxideis added slowly, with mixing, to prevent high local concentration ofepoxide and relatively low local concentration of stabilizer fromdeveloping in the batch. Shortly after the addition of epoxide, a largeexotherm is quickly achieved. It has been found that at exotherms up toeven 180° C. to about 190° C. are achieved in the process of theinvention without any detectable gelling of the fluid.

Following the completion of the hydrosilation reaction, the reactionmixture is devolatilized to remove excess olefin epoxide and lowmolecular weight linear and cyclic siloxane light ends. Devolatizationis preferably accomplished in vacuo and at an elevated temperature. Thetemperature of the so-called "stripping" step in the process of theinvention is at between about 100° C. and about 250° C. Preferably thisheating step is from between about 125° C. and about 225° C., and mostpreferably the stripping step is performed at between about 150° C. andabout 200° C. The-pressure of the stripping step is generally preferredto be below atmospheric, as such reduced pressure aids in the release ofvolatile molecules from the epoxysilicone reaction product. Thus thelower the pressure that can be conveniently obtained, the better.Preferred in the stripping step in the process of the invention arepressures less than about 25 torr. Most preferred for this process stepare pressures below about 10 torr. A rotary evaporator, used as known inthe art, is conveniently employed in the devolatization step of theprocess of the invention. "Thin film" or "wiped film" evaporators arealso conveniently employed to efficiently remove light ends incommercial processing.

The epoxysilicones produced by the process of the invention can beconveniently applied to a substrates including paper, metal, foil,polyethylene coated Kraft paper (PEK), supercalendered Kraft paper(SCK), polyethylene films, polypropylene films and polyester films. Ingeneral, coating can be applied to these substrates at the desiredthickness as is known in the art. For example, compositions of theinvention are readily applicable by doctor blade in a laboratorysetting. For applications as a release coating, the epoxysiliconecompositions are applied at a thickness of between about 0.1 mil and 10mils; it is also convenient to refer to such coatings in terms of "coatweights", typically 1 g/m². Coatings can thereafter be cured thermally,as exemplified below and known in the art.

Due to the highly controllable conditions of the reaction and efficientstabilization of the product of the invention, many heretofore difficultepoxy-functional siloxanes can be easily and routinely prepared. Forexample, compounds such as M.sup.ε M.sup.ε and (D.sup.ε)₄ which arenormally difficult to prepare due to their high reactivity, are easilyprepared by the process of the invention. Additionally, as exemplifiedbelow, the incorporation of a tertiary amine stabilizer in the reactionmixture prior to the addition reaction can significantly lower theviscosity of the resultant fluid as compared to reactions wherestabilizer is added after the addition reaction, as the oxirane ringopening is greatly suppressed or eliminated in the former case but notin the latter. The process of the invention thus makes possible theheretofore unavailable ability to manufacture highly reproducibleepoxysilicone fluids, particularly with respect to viscosity, therebygreatly reducing the batch-to-batch inconsistencies previouslyassociated with the production epoxysilicones.

EXPERIMENTAL

Unless otherwise indicated, all resins and catalysts are available fromGeneral Electric Silicones, Waterford, N.Y. In the shorthand notation ofpolymer structure herein, the following apply:

    ______________________________________                                        M represents (CH.sub.3).sub.3 SiO.sub.0.5 ;                                   M.sup.ε  represents                                                                 ##STR1##                                                        M.sup.H represents                                                                         (CH.sub.3).sub.2 HSiO;                                           M.sup.Vi represents                                                                        (CH.sub.2CH)(CH.sub.3).sub.2 SiO.sub.0.5 ;                       D represents (CH.sub.3).sub.2 SiO;                                            D' represents                                                                              OSi(CH.sub.3).sub.2 CH.sub.2 CH.sub.2;                           D.sup.ε  represents                                                                 ##STR2##                                                        D.sup.H represents                                                                         (CH.sub.3)(H)SiO; and,                                           ______________________________________                                    

subscripts indicate the number of such units in the polymer.

EXAMPLE 1

Two hundred grams of an 18 cstk viscosity silicone fluid (grade 88405),of approximate structure MD₁₅ D^(H) ₄ M, 0.19% H, were charged to a 1liter flask. 0.025 grams of methyldicocoamine, CH₃ (C₁₈ H₃₇)₂ N, wereadded, followed by 0.6 grams of a 2% solution oftris(triphenylphosphine) rhodium trichloride, also known as Wilkinson'scatalyst, in 4-vinylcyclohexene oxide (VCHO). This mixture was agitatedat 115° C. as 50 grams VCHO were added dropwise. No exotherm or otherovert evidence of reaction was detected at this time, and after a 2 hourhold at this temperature, FTIR examination of the reaction mixture,monitoring the strong SiH absorbance at 2200 cm⁻¹, confirmed that noloss of SiH had occurred. At this point, 0.1 gram of a solution of RhCl₃[(CH₃ (CH₂)₃)₂ S]₃ in ethanol containing 1.364 rhodium, by weight, wasadded to the reaction mixture. An immediate sharp exothermic responsetook place, with the batch temperature rising to about 180° C. within afew seconds of the addition of catalyst. Under these conditions, thehighly reactive epoxysilicone formed in the absence of any dispersingmedium would have quickly crosslinked to form a gel had the tertiaryamine stabilizer not been present. The mixture was subsequently strippedof light ends in vacuo at 160° C. for one hour. 225 grams of a 87.8 cstkfluid product was obtained. This product had a refractive index of n_(D)²⁵ =1.4233 and a solids content per 150° C., 45 minute weight loss testof 97.5%.

COMPARATIVE EXAMPLE 2

An epoxysilicone product was made as in Example 1 using the sameethanolic solution of Rh[(CH₃ (CH₂)₃)₂ S]₃, with the exception that thetertiary amine was not present in the mixture at the time of the VCHOfeed. VCHO addition was at 110° C. followed by a two hour hold at thattemperature to give a complete reaction of SiH, as judged by FTIR. 0.025grams of methyldicocoamine stabilizer was then introduced into themixture, after which the mixture was devolatilized as in Example 1. Thisreaction protocol yielded 225 grams of a 97 cstk viscosity fluid, with arefractive index n_(D) ²⁵ =1.4235. Solid content was measured at 97.4%.It should be noted that the epoxysilicone product of Comparative Example2 is 10% higher in viscosity than the product of Example 1.

EXAMPLE 3

All attempts at solvent-free synthesis as above using non-sulfurcontaining platinum catalysts and in the absence of any inert dispersingmedium resulted in gelation during the VCHO feed into the reactionmixture. This was even true when the temperature of the mixture was keptat 75° C. or less.

EXAMPLE 4

256 g (2.06 moles) of 4-vinylcyclohexeneoxide were weighed into a 2liter flask with 400 grams toluene, 0.04 grams CH₃ (C₁₈ H₃₇)₂ N andsufficient RhCl₃ [(CH₃ (CH₂)₃)₂ S]₃ to furnish 2 ppm rhodium in thecomplete reaction mixture. The agitating solution was brought to 100°C., when 134 grams (1.00 mole) of 1,1,3,3-tetramethyldisiloxane (M^(H)M^(H)) were added dropwise over a 30 minute period. Following theaddition, reflux temperature was raised to 115° C. (that of toluene),indicating that the disiloxane (bp 72° C.) had completely reacted withVCHO. After 2 hours hold at 115° C., FTIR analysis detected no unreactedSiH. Toluene and excess VCHO were stripped off in vacuo, leaving 375grams yield (98% of theoretical) of 23.4 cstk mobile fluid product,refractive index=1.4740 (25° C.) vs. literature value= 1.4731 (E. P.Plueddemann et al., J. Amer. Chem. Soc. 81, 2632 (1959)). This materialcan be represented as M.sup.ε M.sup.ε, ##STR3## and has been shown to bean extremely reactive diepoxy monomer (Crivello and Lee, Proceedings ofA.C.S. Division of Polymeric Materials: Science and Engineering, Vol 60,pg 217, (1989); also Eckberg and Riding, ibid., pg 222).

COMPARATIVE EXAMPLE 5

The synthesis of M.sup.ε M.sup.ε was carried out as described in Example4, except that tris(triphenylphosphine) rhodium (I) chloride(Wilkinson's catalyst) was substituted for the dibutylsulfide complex,and the tertiary amine stabilizer (CH₃)(C₁₈ H₃₇)₂ N was only added tothe reaction mixture after all SiH had reacted. Removal of solvent andexcess VCHO afforded a good yield of a 98 cstk fluid product, N_(D) ²⁵=1.4750. It should be emphasized that this material is 4 times theviscosity of the product described in Example 4, indicating that epoxycrosslinking had occurred during the synthesis.

COMPARATIVE EXAMPLE 6

Several attempts to synthesize M.sup.ε M.sup.ε using platinumhydrosilation catalysts were carried out via addition of 1 mole M^(H)M^(H) to 2 moles VCHO in toluene at 60°-80° C., using the Karstedtplatinum catalyst at a concentration of 5 ppm Pt. The reaction proved tobe unpredictable. In about half of the syntheses, gelation occurred verysuddenly midway through the disiloxane additions, accompanied byvigorous and uncontrollable exothermic response. Isolable products wereobtained in some of these experiments, with viscosities ranging from 70to 1000 cstk. It is apparent that the highly reactive diepoxydisiloxane,M^(") M^("), cannot be reliably nor reproducibly processed usingstandard platinum hydrosilation catalysts.

EXAMPLE 7

A low viscosity liquid silicone resin, approximate stoichiometry M₂ ^(H)Q, where "Q"=--SiO_(4/2) --, 1.0 wt % H (in the form of H(CH₃)₂SiO_(1/2) --), designated 88104, is a highly reactive crosslinker usefulfor certain thermal two part RTV applications. Attempts to produce theaddition product of this material with stoichiometric amounts of VCHOusing non-stabilized platinum catalysts such as the Karstedt orLamoreaux catalyst always ended in rapid onset of gelation accompaniedby uncontrollable exotherms, regardless of how the addition was carriedout, or how much solvent diluent was present, and even at additiontemperatures less than 50° C. We then carried out the synthesis using analkylsulfide platinum complex in the presence of the tertiary aminestabilizer, as follows:

100 g of M₂ ^(H) Q resin, 1.0 mole H, were weighed into a 2 liter flaskwith 0.025 grams (CH₃)(C₁₈ H₃₇)₂ N, 200 grams toluene, and 0.25 grams ofa 1% solution of dichlorobis(diethylsulfide) platinum (II) catalyst inmethylenechloride. The solution was brought to 100° C., when 136 gramsVCHO (1.10 mole) were added dropwise over a 60 minute period. Anexothermic response maintained the reaction mixture at 115° C. refluxwithout external heating shortly after commencing this addition.Following the VCHO feed, no SiH peak was detectable in the infraredspectrum of the product. Removal of solvents and excess VCHO afforded202 grams (90% yield) of a viscous fluid product, 8000 cps viscosity,N_(D) ²⁵ =1.4806. This product was quite miscible with 1 wt percent(4-octyloxyphenyl)(phenyl)iodonium hexafluoroantimonate photocatalyst,and the photocatalyzed mixture rapidly cured to a hard, glossy 2 milcoating on exposure to only 16 mJ/cm² UV light when coated on apolyethylene sheet. Obviously, the very high epoxy content of thismaterial renders it extremely reactive as well as miscible with theiodonium photocatalyst.

It is understood that various other modifications will be apparent toand can be readily made by those skilled in the art without departingfrom the scope and spirit of this invention. Accordingly, it is notintended that the scope of the claims appended hereto be limited to thedescription set forth above but rather that the claims be construed asencompassing all of the features of patentable novelty which reside inthe present invention, including all features which would be treated asequivalents thereof by those skilled in the art to which the inventionpertains.

We claim:
 1. A process for producing epoxysilicone comprising the stepsof:(a) preparing a mixture comprising an SiH-containing silane orsiloxane and a tertiary amine; (b) adding to the mixture a hydrosilationcatalyst which is a metal complex of the formula RhX₃ (R¹ ₂ S)₃ or PtX₂(R¹ ₂ S)₂ wherein X is a halogen other than F⁻, and each R¹ group isindependently C.sub.(1-30) alkyl, aryl, alkaryl or aralkyl, each ofwhich may be substituted or unsubstituted; and, (c) reacting byhydrosilation addition an olefin epoxide with the mixture of step (b) toproduce an eopxysilicone.
 2. The process as set forth in claim 1,wherein in step (a) said tertiary amine is selected from the groupconsisting of substituted or unsubstituted trialkylamines,triarylamines, alkarylamines, aralkylamines and mixed tertiary aminescomprising more than one of these substituents.
 3. The process as setforth in claim 2, wherein in step (a) said tertiary amine ismethyldicocoamine.
 4. The process as set forth in claim 1, wherein instep (b) said hydrosilation catalyst is

    RhCl.sub.3 [(CH.sub.3 (CH.sub.2).sub.3).sub.2 S].sub.3

or

    PtCl.sub.2 [(CH.sub.3 CH.sub.2).sub.2 S].sub.2.


5. The process as set forth in claim 1, wherein in step (c) said olefinepoxide is selected from the group consisting of limoneneoxide,4-vinylcyclohexene oxide, allylglycidylether, glycidylacrylate,7-epoxy-1-octene, vinylnorborene monoxide and dicyclopentyldienemonoxide.
 6. The process as set forth in claim 1, whereinin step (a)said tertiary amine is selected from the group consisting oftrialkylamines, triarylamines, alkarylamines, aralkylamines and mixedtertiary amines comprising more than one of these substituents; in step(b) said hydrosilation catalyst is of the formula RhX₃ (R¹ ₂ S)₃ or PtX₂(R¹ ₂ S)₂ wherein X is a halogen other than F- and each R1 group isindependently C.sub.(1-30) alkyl, aryle, alkaryl, or aralkyl, each ofwhich may be substituted or unsubstituted; and in step (c) said olefinepoxide is selected from the group consisting of limoneneoxide,4-vinylcyclohexene oxide, allylglycidylether, glycidylacrylate,7-epoxy-1-octene, vinylnorborene monoxide, and dicyclopentyldienemonoxide.